Ethyl Corporation

William E Wright

Edward F Zaweski

Gordon G Knapp

David N Roark

Bryan T Davis

Donald S Matteson

An improved process for the preparation of certain fluorinated aromatic diamines is disclosed. The step-wise addition of an alkali metal hydroxide to the starting material produces increased yields of higher purity diamine product.

Process for the preparation of fluorinate aromatic diamine

Copolyimides and their precursors are disclosed comprising units having aromatic sulfone and aromatic fluoroaliphatic groups. These copolymers are represented by the formula ##STR1## wherein Ar' and Ar' are the same or different and are ##STR2## where Z is a chemical bond, ##STR3## Ar is the tetravalent residue of a tetracarboxylic acid or acid dianhydride or di- or tetraester thereof where the ratio of x to y is from about 1:99 to about 49:51. These copolymers have improved processing temperatures and can be readily formed into sheets. They may also be used in applications such as hot-melt adhesives or prepregging.

Copolyimide aromatic sulfone-fluoroaliphatic resin composition

An additive composition of boronated phenolic antioxidant and anti-haze diol capable of complexing with boric acid as well as organic material protected by the additive composition. A hydrolytically stable additive composition comprising a boronated phenolic antioxidant and a diol member capable of reacting with boric acid formed as a hydrolysis product to form a stable ring structure soluble in a substrate. The additive composition prevents or cures a haze caused by hydrolysis.

Haze-free boronated antioxidant

A polyimide precursor suitable for use in the pseudo hot-melt prepregging process is described. It consists essentially of a mixture of (a) about 40 to about 70 percent by weight of a substantially equimolar mixture of (i) 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane or 2,2-bis[4-(3-aminophenoxy)phenyl]hexafluoropropane, or both, and (ii) lower alkyl diester of aromatic tetracarboxylic acid; (b) about 2 to about 50 percent by weight of polyamide (polyamic acid or ester) producible from components (i) and (ii); and (c) about 10 to about 50 percent by weight of solvent with the proviso that the mixture is a clear resinous solid at 25.degree. C. and is a viscous, tacky, varnish-like liquid at a temperature falling in the range of 40.degree. C. to 100.degree. C. Also described are use of the polyimide precursors in preparing coated paper webs useful in preparing paper-backed prepregging tape, and use of the coated paper webs in preparing the paper-backed prepregging tapes.

Polyimide precursor and pseudo hot-melt prepregging process employing

Prepreg precursors and other normally non-flowable resinous semi-solid or viscous liquid polyimide precursor compositions often need to be transformed into free-flowable liquids without dilution and without causing changes in their chemical composition. Such compositions are composed of (a) a diester of an aromatic tetracarboxylic acid, (b) an aromatic diamine, (c) a polyamic acid producible from (i) an aromatic diamine and (ii) a dianhydride of an aromatic tetracarboxylic acid, and (d) an inert solvent in an amount insufficient to provide a flowable liquid at room temperature. Such compositions readily undergo chemical change (amidization and imidization) when subjected to heating in a conventional oven because of local overheating, and poor heat transfer within the body of the composition. These problems are overcome by subjecting the composition to microwave radiation of intensity sufficient to convert at least a portion of the composition into a flowable liquid without causing a significant change in its chemical composition.

Processing polyimide precursor compositions

An asphaltic composition of enhanced utility for vehicular pavement is described. It comprises a road paving grade of asphalt in admixture with a small amount of an alkylene dithiocarbamate such as methylene bis(dibutyldithiocarbamate) characterized by having a reduced increase in absolute viscosity to original absolute viscosity after thin film aging as measured by ASTM Test D 1754 at 140.degree. F. Such compositions exhibit enhanced resistance to oxidative degradation of the type normally experienced by road paving grades of asphalt.

Asphaltic compositions

Organic material such as lubricating oil is stabilized against gradual oxidative degradation by the addition of aromatic diamines such as 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, mixtures thereof, and the like.

Antioxidant diamine

Diaryl ethers such as 3-phenoxytoluene are made by heating an aromatic hydroxy compound or mixture of such compounds with aluminum or an aluminum phenoxide forming compound such as aluminum trialkyl.

Process for preparing a 3-phenoxytoluene and diphenyl ether

Dialkylphosphites are made by adding PCl.sub.3 to a mixture of water and alkanol and distilling product from the resultant reaction mixture leaving a distillation residue. Alkanol is added to the residue and the mixture reacted at elevated temperature to yield additional dialkylphosphite.

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Baton Rouge, LA, United States of America

William E Wright